title: Analysis of caged xanthones from the resin of Garcinia hanburyi using ultra-performance liquid chromatography/electrospray ionization quadrupole time-of-flight tandem mass spectrometry.
abstract: On-line ultra high-performance liquid chromatography (UHPLC) coupled with electrospray quadrupole time-of-flight tandem mass spectrometry (ESI-QTOF-MS/MS/MS) has been developed for the analysis of a series of caged xanthones in the resin of Garcinia hanburyi. The fragmentation of protonated molecular ions for 12 known cadged xanthones was carried out using low-energy collision-induced electrospray ionization tandem mass spectrometry. It was found that Retro-Diels-Alder rearrangement occurred in the CID processes and produced the characteristic fragment ions, which are especially valuable for the identification of this class of xanthones. The fragmentation differential between some cis-, trans-isomers was uncovered. Computation methods were utilized to rationalize the observed MS behaviors. On-line UHPLC-ESI-MS/MS/MS method has proved to be rapid and efficient in that within 6min, 15 caged scaffold xanthones, including three pairs of epimers and four pairs of isomers in gamboges, were effectively separated and identified. Among them, two known, namely isogambogenin (13) and isomorellinol (14) and one likely new caged Garcinia xanthones from the Garcinia hanburyi were tentatively characterized based on the tandem mass spectra of known ones.
authors.affiliation: Hong Kong Jockey Club Institute of Chinese Medicine, Shatin, Hong Kong, People's Republic of China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhou
authors.forename: Xin
authors.initials: X
authors.lastname: Liu
authors.forename: Jing
authors.initials: J
authors.lastname: Yang
authors.forename: Quan-Bin
authors.initials: QB
authors.lastname: Han
authors.forename: Jing-Zheng
authors.initials: JZ
authors.lastname: Song
authors.forename: Song-Lin
authors.initials: SL
authors.lastname: Li
authors.forename: Chun-Feng
authors.initials: CF
authors.lastname: Qiao
authors.forename: Li-Sheng
authors.initials: LS
authors.lastname: Ding
authors.forename: Hong-Xi
authors.initials: HX
authors.lastname: Xu
mesh_terms: D002851:Chromatography, High Pressure Liquid; D029760:Garcinia / Q000737:chemistry*; D007536:Isomerism; D010936:Plant Extracts / Q000737:chemistry; D012116:Resins, Plant / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization; D053719:Tandem Mass Spectrometry; D013997:Time Factors; D044004:Xanthones / Q000032:analysis* / Q000737:chemistry / Q000302:isolation & purification
chemical_list: D010936:Plant Extracts; D012116:Resins, Plant; D044004:Xanthones